The present invention generally relates to combustion control apparatus for fuel-fired heating appliances and, in representatively illustrated embodiments thereof, more particularly provides apparatus for detecting a burner flashback condition in a fuel-fired appliance, representatively a water heater, and responsively shutting down combustion in the appliance.
Integration of fuel/air premixing type burners into fuel-fired water heaters has presented the potential for such burners operating at certain times and under certain conditions in a “flashback” burning mode in which the burner flame burns within the burner body instead of externally emanating therefrom as intended. It is possible for this flashback burning mode to continue for extended periods of time during which the burner can emit undesirably high levels of carbon monoxide and/or compromise the flammable ignition resistance system of the water heater.
Because of this potential for a flame flashback burning condition in a fuel burner incorporated in a fuel-fired heating appliance such as a water heater, it would be desirable to provide the appliance with a protective system operative to detect a burner flame flashback condition and responsively shut down the appliance.